I bought it last year and use it a lot. I went through a whole box of 14mm x 140 dominoes which equals about 70 tenons meaning I made at least 140 70mm grooves. The bits are well cut and true to size. It's going to be a bit boring, but I'll sharpen it and make 140 more grooves. In fact, I've made over 140 slots on this drill bit, made trial cuts, and done a few experiments for projects. Most of the cuts were made in pine, but I've also used it in white oak for door projects that required 40 toβ¦